import math

data =map(float, raw_input().split(" "))

dx = data[2] - data[0]
dy = data[3] - data[1]

print math.sqrt(dx**2+dy**2) import math math data =map(float, raw_input().split(" ")) data map(float, raw_input().split(" ")) map float raw_input().split(" ") ().split () raw_input split " " dx = data[2] - data[0] dx data[2] - data[0] data[2] data 2 data[0] data 0 dy = data[3] - data[1] dy data[3] - data[1] data[3] data 3 data[1] data 1 print math.sqrt(dx**2+dy**2) math.sqrt math sqrt dx**2+dy**2 dx**2 dx 2 dy**2 dy 2 dx = data[2] - data[0] data[2] - data[0] dx data =map(float, raw_input().split(" ")) map(float, raw_input().split(" ")) data dy = data[3] - data[1] data[3] - data[1] dy
import math

data =map(float, raw_input().split(" "))

dx = data[2] - data[0]
dy = data[3] - data[1]

print math.sqrt(dx**2+dy**2)